Equilibrium conditions (2 forces)
A body under 2 forces is in equilibrium if: forces are collinear, opposite, and equal in magnitude.
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Lesson overview
This lesson brings together the PDF, study notes and chapter flow so you can revise Rotational Equilibrium without losing the thread.
Equilibrium conditions (2 forces)
A body under 2 forces is in equilibrium if: forces are collinear, opposite, and equal in magnitude.
Equilibrium conditions (3 forces)
3 forces in equilibrium: their vector sum = 0. They are coplanar and concurrent.
Support reaction (R)
Force exerted by the support on the object. On horizontal surface: R = P (vertical).
Moment about an axis
M(F) = F · d where d is the distance (lever arm) between the line of action of F and the axis.
Rotational equilibrium
The algebraic sum of moments is zero: ΣM = 0.
Application 1 - Equilibrium of a solid body
Industrial example.
Application 2 - Equilibrium of a solid body
Industrial example.
Application 3 - Equilibrium of a solid body
Industrial example.
Application 4 - Equilibrium of a solid body
Industrial example.
Application 5 - Equilibrium of a solid body
Industrial example.
Experiment 1 - Equilibrium of a solid body
Lab protocol.
Experiment 2 - Equilibrium of a solid body
Lab protocol.
Experiment 3 - Equilibrium of a solid body
Lab protocol.
Experiment 4 - Equilibrium of a solid body
Lab protocol.
Experiment 5 - Equilibrium of a solid body
Lab protocol.
Scientific method
Read data, identify the system, choose the model, write relations with SI units, then check the order of magnitude.
Exam focus
Precise definitions, labelled diagrams, unit conversions, document analysis, and justified numerical results.
Forces and motion
Always state the reference frame, system, applied forces, and vector directions before calculating.
Units
Force in newtons (N), mass in kg, distance in m, speed in m/s.